The effects of stimulus rate and electrode montage on the auditory brainstem response in infants

Abstract

Purpose

This study investigates the effects of different stimulus repetition rates and multiple electrode recording montages (ipsilateral, contralateral, horizontal, and vertical) on the auditory brainstem response (ABR) wave V amplitude and latency in infants.

Methodology

Eleven healthy infants with the mean age of 4.36 ± 1.95 months were involved in this repeated-measure design study. Prior to the actual data collection, several preliminary audiological assessments (otoscopic examination, tympanometry, otoacoustic emission and ABR screening at 35 dB normalized hearing level (dBnHL)) were conducted to ensure that all participants had normal auditory functions. Once qualified, the participants were tested with the ABR using 100-microsecond clicks recorded under the four electrode montages at two stimulus repetition rates (19.1 and 61.1 Hz) and at an intensity level of 35 dBnHL.

Results

The ABR was shown as present in all participants in all four electrode montages and both stimulus repetition rates. The largest wave V amplitude was recorded in the vertical montage for both stimulus repetition rates. No significant changes (P > 0.05) were noted in the wave V amplitudes in all electrode montages when the stimulus repetition rate was changed from 19.1 to 61.1 Hz.

Conclusion

This study confirmed that combining the vertical montage with high stimulus repetition rates of 61.1 Hz at 35 dBnHL has the potential for detecting auditory dysfunction in infants, because of the larger and more stable wave V amplitude.

Keywords:

• Auditory brainstem response (ABR)
• Stimulus repetition rate
• Electrode montage
• Lower intensity level
• Infant

Acknowledgments

The authors would like to acknowledge the International Islamic University Malaysia Endowment fund for their financial support in conducting this study (grant number: EDW B0904-269). We also would like to acknowledge Dr. Wan Asylnn Salwani Wan Ahmad for her assistance in giving her expert opinion about this study.